Locking device



Patented Mar. 13, 1934 UNITED sTATEs PATENT OFFICE Looms DEVICE Application' September 29, 1930, Serial N0. 4.85273 1 Claim.

It is often necessary, when using electrical devices which derive their current from an electrieal outlet or receptacle which is situated inthe base board or in the wall of a room to carry the electrical device about. In moving the electrical device, a strain is often put on the cord which is connected to the attachment plug cap and often times this strain is sufficient to disengage the cap from the receptacle thereby breaking the electrical connection.

This invention relates to devices for securing the members of a separable electric tting together, such as is described and claimed broadly in my eopending application Serial No. 330,850,

No. 1,874,334. My present invention relates more particularly to a device which is adapted to cooperate with the flush plate of an electric receptacle and to hold an attachment plug cap in circuitclosing engagement with the receptacle.

lt is an object of my invention to provide a simple and eiiicient locking device which can be inexpensively made and which will act to hold the attachment plug and the receptacle together until the locking device is released manually.

Referring to the drawing:-

l'igure 1 is a perspective View of a flush plate and receptacle with which is associated my new locking device. This ligure also shows in perspective an attachmentplug cap in position to be inserted in the receptacle.

Figure 2 -isa side elevation view of the construction shown in Figure 1 but with the attachment plug cap inserted in the receptacle and se- 35 cured by my new locking device.

Figure 3 is a mid-section view of my locking device.

Figures 4 and v5 are perspective views oi the two parts of the locking device. v

Referring to the drawing, indicates a conventional flush plate to which is secured by screws l1 a conventional receptacle 12 in which are contact apertures 13. An attachment plug cap 14, having contact blades which are adapted to be inserted in the apertures 13 to complete the electric circuit, has a strain relief tting likev that shown in"my Patent No.- 1,874,334. tting comprises a ring '18 adapted to be slipped over the working end of the attachment plug cap 14 and to rest against an annular shoulder 20 formed on the cap.I Extending from opposite sides of an outwardly oiset flange 22- on the ring 18 are arms 24, the free ends of which are shaped to form gripping jaws having laterally projecting lugs in filed January 3rd, 1929 patented August 30, 1932,

which are apertures to receive clamping screws to 'clamp the jaws together and grip the cable C. l'lor a purpose which will presently appear, two

vnotches 26 are formed in the ange 22 in diametrically opposed positions. o

The .locking device which I employ comprises relatively rotatable outer and inner ring shaped members 28 and 32 which may be stamped from sheet metal and which have the same inside diameter but the member 28 has a greater outside diameter. The member 28 has two lateral extensions 30 which are apertured to permit the insertion of the screws 11 in order that the member may be secured to the iiush plate 10 and receptacle 12 by the same screws that secure the plate and receptacle together. The inner periphery of the member 28 is slightly raised or oiiset from the body of the ring to permit the member 32 which is approximately ofthe same size as the offset portion 3l, to lie beneath the member 28 with the lower surfaces of both members in 'the same plane.

Projecting up from the inside of the member 32 are arms 34 having bent over ends 36 for the purpose of engaging flange 22 of the strain res@ lief tting in order to hold the cap 14 in engagement with 'the receptacle when all the parts are assembled. These arms also serve to hold the members 28 and 32 together during shipment and at other times when they are not secured to a face plate. For this latter purpose the mid portion of the arms are bent backwardly over the ring portion of the member 32. Thus when the members 28 are together, an effort to separate them will cause the mid-portion of the arms to engage the oiset portion 31 of the member 28 thereby preventing their separation. In order to assemble and disassemble the member 32 and the member 28 without distorting the arms 34 a notch 38 is cut in the. oiset portion 31 of the member 28 to receive one of the arms 34. The notch is of .such depth that when one of the arms 34 lies in it the other arm will just clear the inner periphery of the member 28 as the members 28 and 32 are pushed together. f f

Now the locking device may be secured on th face plate 10 and the member 32 may be rotated relative to the ring 28 until the lugs 34 are in position to register with the notches 26 of the attachment plug cap at the moment when the prongs 15 of the cap are being inserted into apertures 13 of the receptacle. As soon as the prongsy 15 have been pushed home and the circuit completed between the receptacle and the attachment 110 plug cap, the member 32 may be rotated by means of the lugs 34 and the inwardly turned ends36 of these lugs will overlie the flange 22, thus preventing the cap from being pulled out of engagement with the receptacle.

Thus it will be seen that I have provided a simple locking device which may be inexpensively manufactured in large quantities from sheet metal by means of a. die press. Obviously many modications within the scope of this invention will occur to those skilled in the art and therefore I do not limit myself to the specic embodiment shown.

or separated.

ARVID H. NERO.

miy 

